Jumping Spider on Orchid
A Jumping Spider (Sitticus pubescens) looks for prey from the blossom of a Dendrobium orchid.
Jumping spiders belong to the largest Family of spiders, the Salticidae, with more than 5,800 described species. They are found around the globe, more commonly in tropical environments, although some species even thrive in the frigid Himalayas. Over 300 species exist within North America.
Jumping spiders have swift reflexes and excellent leaping abilities. The small 1-25mm (0.04–0.98 inch) spiders can jump more than 25 times their own size using a well-developed internal hydraulic system that extends their limbs by altering the pressure of body fluid (hemolymph) within them. This enables the spiders to jump remarkable distances without large muscular legs like a grasshopper.
Unlike most spiders, jumping spiders hunt actively during the daytime. They have the keenest vision of all spiders, being able to detect movement up to 18" around them. Their night vision, however, is poor. Jumping spiders have 8 eyes, 4 on the face and 4 on the highest point of the carapace. Their overall field of view is nearly 360-degrees. The 2 long and tube-like eyes located at the center of the face provide stereoscopic vision, are moveable and have very high resolution (11min visual angle), but very limited field of view (2-5 degrees). In contrast, the other eyes are fixed and have low acuity but wide field of view. Some of the eyes see only green wavelengths, some blue and UV-light, and others have tetrachromatic color vision with sensitivity extending into the ultraviolet range.
Jumping spiders do not construct snare webs but they do produce silk to mark retreats, protect eggs, and as a dragline while jumping to allow the spiders to control their fall and retrace their steps.
Jumping spiders are particularly abundant in grassland and prairie environments, where they prey upon bollworms, cotton leaf worms, webworms, cotton flea hoppers, stinkbugs, leafhoppers and mosquitoes.